Contents • This lecture will cover: • What is a digital image? • What is digital image processing? • History of digital image processing • State of the art examples of digital image processing • Key stages in digital image processing

What is a Digital Image? Images taken from Gonzalez & Woods, Digital Image Processing (2002) • A digital image is a representation of a two-dimensional image as a finite set of digital values, called picture elements or pixels

What is a Digital Image? (cont…) • Common image formats include: • 1 sample per point (B&W or Grayscale) • 3 samples per point (Red, Green, and Blue) • 4 samples per point (Red, Green, Blue, and “Alpha”, a.k.a. Opacity) • For most of this course we will focus on grey-scale images

What is Digital Image Processing? • Digital image processing focuses on two major tasks • Improvement of pictorial information for human interpretation • Processing of image data for storage, transmission and representation for autonomous machine perception • Some argument about where image processing ends and fields such as image analysis and computer vision start

History of Digital Image Processing Early digital image Images taken from Gonzalez & Woods, Digital Image Processing (2002) • Early 1920s: One of the first applications of digital imaging was in the news-paper industry • The Bartlane cable picture transmission service • Images were transferred by submarine cable between London and New York • Pictures were coded for cable transfer and reconstructed at the receiving end on a telegraph printer

History of DIP (cont…) Images taken from Gonzalez & Woods, Digital Image Processing (2002) Improved digital image Early 15 tone digital image • Mid to late 1920s: Improvements to the Bartlane system resulted in higher quality images • New reproduction processes based on photographic techniques • Increased number of tones in reproduced images

History of DIP (cont…) Images taken from Gonzalez & Woods, Digital Image Processing (2002) A picture of the moon taken by the Ranger 7 probe minutes before landing • 1960s: Improvements in computing technology and the onset of the space race led to a surge of work in digital image processing • 1964: Computers used to improve the quality of images of the moon taken by the Ranger 7 probe • Such techniques were usedin other space missions including the Apollo landings

History of DIP (cont…) • 1980s - Today: The use of digital image processing techniques has exploded and they are now used for all kinds of tasks in all kinds of areas • Image enhancement/restoration • Artistic effects • Medical visualisation • Industrial inspection • Law enforcement • Human computer interfaces

Examples: The Hubble Telescope • Launched in 1990 the Hubble telescope can take images of very distant objects • However, an incorrect mirror made many of Hubble’s images useless • Image processing techniques were used to fix this

Examples: Artistic Effects • Artistic effects are used to make images more visually appealing, to add special effects and to make composite images

Examples: GIS (cont…) Images taken from Gonzalez & Woods, Digital Image Processing (2002) • Night-Time Lights of the World data set • Global inventory of human settlement • Not hard to imagine the kind of analysis that might be done using this data

Examples: PCB Inspection • Printed Circuit Board (PCB) inspection • Machine inspection is used to determine that all components are present and that all solder joints are acceptable • Both conventional imaging and x-ray imaging are used

Summary • We have looked at: • What is a digital image? • What is digital image processing? • History of digital image processing • State of the art examples of digital image processing • Key stages in digital image processing • Next time we will start to see how it all works…